For example, it is desirable to improve the performance of a semiconductor device.
According to one embodiment, a method for manufacturing a semiconductor device is disclosed. The method can include forming a trench and exposing a portion of a first film at a bottom portion of the trench by removing a portion of a second film by performing dry etching using a gas including a first element. The second film is provided on the first film. The first film includes Alx1Ga1-x1N (0≤x1<1). The second film includes Alx2Ga1-x2N (0<x2<1 and x1<x2). The method can include performing heat treatment while causing the portion being exposed of the first film to contact an atmosphere including NH3, forming an insulating film on the portion of the first film after the heat treatment, and forming an electrode on the insulating film. The insulating film has a first position at a center in a first direction. The first direction is from the portion of the first film toward the electrode. A concentration of the first element at the first position is 1×1018 cm−3 or less.
According to another embodiment, a method for manufacturing a semiconductor device is disclosed. The method can include forming a trench and exposing a portion of a first film at a bottom portion of the trench by removing a portion of a second film provided on the first film, the first film including Alx1Ga1-x1N (0≤x1<1). The second film includes Alx2Ga1-x2N (0<x2<1 and x1<x2). The method can include performing heat treatment at a temperature of 790° C. or less while causing the exposed portion of the first film to contact an atmosphere including NH3.
According to another embodiment, a method for manufacturing a semiconductor device is disclosed. The method can include forming a trench and exposing a portion of a first film at a bottom portion of the trench by removing a portion of a second film provided on the first film. The first film includes Alx1Ga1-x1N (0≤x1<1). The second film includes Alx2Ga1-x2N (0<x2<1 and x1<x2). The method can include performing heat treatment at a temperature of 900° C. or less while causing the exposed portion of the first film to contact an atmosphere including NH3.
Various embodiments will be described hereinafter with reference to the accompanying drawings.
The drawings are schematic and conceptual; and the relationships between the thickness and width of portions, the proportions of sizes among portions, etc., are not necessarily the same as the actual values thereof. Further, the dimensions and proportions may be illustrated differently among drawings, even for identical portions.
In the specification and drawings, components similar to those described or illustrated in a drawing thereinabove are marked with like reference numerals, and a detailed description is omitted as appropriate.